US officials in Karachi were last night leading the interrogation of the suspected al-Qaida member, Ramzi Binalshibh, as they claimed major successes in the war on terrorism, including the alleged break-up of a terrorist cell in upstate New York.

Pakistan said it had captured another senior al-Qaida figure, but refused to identify him or give his nationality. There was speculation that this could be Khalid Sheikh Mohammed, a much more senior al-Qaida figure who investigators believe has also been hiding in Karachi. Binalshibh, a Yemeni, was described as an aide to Mr Mohammed, who is thought to have been a senior figure in the September 11 conspiracy.

Mohammed, a Kuwaiti, is also wanted in connection with a failed plot hatched in Manila in 1995 to bomb American jets as they flew over the Pacific. At first police believed they had killed him in a gun battle in Karachi last Wednesday. Intelligence officers later said the identification was wrong.

Binalshibh and Mohammed appeared together in an interview with the Arab television network al-Jazeera, filmed at a hideout in Karachi several weeks ago, in which they discussed in detail the planning for the September 11 at tacks. Pakistani authorities say they will send Binalshibh overseas for trial.

Washington said yesterday it wanted to see him transferred to the US. "We will be working with the Pakistani officials to make sure he gets to the right place," President George Bush's national security adviser, Condoleezza Rice, said in an interview with Fox News.

Another apparent new success emerged yesterday with the reported confession of Omar al-Faruq, who was arrested in Indonesia three months ago and handed over to US interrogators in Afghanistan. He broke down last week and admitted to being al-Qaida's top operative in south-east Asia, Time magazine said.